[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Terahertz Spectroscopy of Different Phenotypes of Arabidopsis Thaliana

摘要： The recent surge in ‘Precision agriculture’ is fueled by the acute need of food security felt worldwide to feed the global burgeoning population. To this effect, various optical techniques have recently been employed to characterize the biochemical processes in various parts of the plants [1]. Terahertz (THz) region (0.3 – 10 THz) has gathered momentum in this field as it is biologically safe, can penetrate food packaging and most importantly, has fingerprinting ability of various organic and inorganic molecules due to active rotational and vibrational modes [2]. Moreover, unlike other optical spectroscopic techniques, THz time domain spectroscopic (THz-TDS) technique records the information in form of THz electric field; which once converted to frequency domain provides both amplitude and phase information [3]. Additionally, THz waves are highly absorbed by water which in turn can be utilized for quantitative water status monitoring in plants [4]. In this work, we have used THz-TDS with a bandwidth over 5 THz for the detection of biochemicals present in two different T-DNA insertion mutants in two independent genes of Arabidopsis thaliana (Col-0 Columbia ecotype). The plants were grown from mutant seeds in controlled environment. For easier optical access to all parts of the plants, the seedlings were grown parallel to the surface in a petri dish of plant growth medium. Liu et al. has already reported successful discrimination of transgenic Soybean seeds using THz spectroscopy [5]. We have recorded spectroscopic data of several parts of all the mutant plants which were 5, 7, 12 and 13 days old kept under identical conditions. The time domain spectrum obtained from the experiment was converted to frequency domain. Figure 1 shows the frequency domain spectrum of one such set of spectroscopic data collected from the stem part of the two different mutants compared to wild type control Col-0 plants. As it is evident from the spectrum, there are many absorption peaks corresponding to water and other biochemical molecules. For example, the peaks at 1.7 THz and 2.6 THz corresponds to sucrose present in the plants and in the nutri-solution which has been taken as the reference [2]. Our ongoing study involves careful analysis of the variations of the molecular absorption peaks for different mutants which would not only enable a label-free genetic identification, but also would help in our understanding of the underlying shift in biochemical processes contributed by the specific gene.